This invention relates generally to a fastener used for connecting a first link member to a second link member in a linkage assembly for a vehicle seat track assembly and, more particularly, to a fastener having a head portion, a centering post, and a self tapping portion that is used to rotatably secure the first link member to the second link member while eliminating any lateral free play in the linkage assembly.
Linkage assemblies are often used in vehicle seat track assemblies to provide various functions including seat adjustment capability. Linkage assemblies typically include two or more link members, which are joined to each other by various methods. The link members typically receive input from an adjuster control member that causes the link members to rotate relative to one another to achieve a desired position. In known linkage assemblies, as the link members rotate relative to each other there has typically been lateral free play or movement between the link members. This lateral free play is detrimental to the stability of the adjuster control member and the linkage assembly.
Attempts to eliminate the lateral free play between the link members of a linkage assembly have been made. In the past, one method has been to incorporate a bushing to permit the link members to rotate relative to each other and a pin that is press fit into the bushing to secure the link members to each other. One disadvantage with this method is that assembly of the parts into the linkage assembly can be especially difficult because it requires clamping pressure, which damages the bushing if there is any misalignment of the pin relative to the bushing. In addition, this method requires at least two parts, namely, a bushing and a press fit pin. One other disadvantage with this method is that the initial step of aligning the bushing and press fit pin with apertures in the link members can be very difficult.
Thus, it is desirable to eliminate the use of bushings and press fit pins to join the link members of a linkage assembly. It is also desirable to provide a fastener for connecting the link members of the linkage assembly that has a reduced number of parts as compared to the current methods. Additionally, it is desirable to provide a fastener for a linkage assembly that is self-centering and thus, reduces assembly time and mis-alignment problems.